The Financial Services Authority has been accused of preventing up to 10,000 businesses from accessing a compensation scheme for those who believe they have been mis-sold “swaps” — interest rate hedging products.

The watchdog has apologised and changed the wording of documents which show who can take part in the authority’s redress scheme. The change came after a small property company which believed that it was mis-sold a swap by Royal Bank of Scotland was barred from taking part in the scheme because it was “intermediary”.

The FSA originally announced that swaps sold to “unsophisticated” customers with turnover of up to